An inflator for inflating an air bag is actuated upon the occurrence of a vehicle collision. The inflator then emits inflation fluid which is directed to flow into the air bag. The inflation fluid inflates the air bag to an inflated condition in which the air bag extends into the vehicle occupant compartment. When the air bag is inflated into the vehicle occupant compartment, it restrains an occupant of the vehicle from forcefully striking parts of the vehicle as a result of the collision.
The air bag and the inflator are typically assembled together as parts of an air bag module. In addition to the air bag and the inflator, the air bag module includes a reaction canister which contains and supports the air bag and the inflator in the vehicle. The reaction canister typically has an inner portion containing the inflator and an outer portion containing the air bag. The inflator is fixed to the inner portion of the reaction canister. The air bag is connected to the outer portion of the reaction canister, and is inflatable outward through a deployment opening in the outer portion of the reaction canister. A deployment door extends over the deployment opening to conceal the air bag and the other parts of the module from the vehicle occupant compartment.
When the inflator is actuated, the reaction canister directs the inflation fluid to flow from the inflator into the air bag. As the inflation fluid enters the air bag, it moves the air bag forcefully outward against the deployment door at the deployment opening. The deployment door is ruptured by the force of the fluid pressure in the air bag, and is moved out of the path of the air bag as the air bag inflates outward from the reaction canister through the deployment opening and into the vehicle occupant compartment.